2000 Thomas/Freightliner Cummins 24v won't start.

[Christian-]

Hey folks,

I'm helping a friend with a bus he bought and we've run into a no start condition.

He originally thought it was the starter so he replaced that. I've since bench tested the new starter and can confirm it works.

We have good battery voltage and I've confirm the positive battery terminal carries good voltage to the starter.

When we turn the key to run there's a click somewhere that we can't quite place and when turned to start we get nothing.

I did some looking around but haven't been able to find decent wiring diagrams to track down the starter wiring or any ignition interlocks that may be in place.

One thing to note that may not be relevant: there was a speaker on a circuit board that was buzzing when you turned the key to run and my friend removed that from the board.

Any suggestions on where to start would be awesome. If anyone has any manuals or wiring diagrams they could share that would be great also.

Thanks in advance!

[Jolly Roger bus 223]

the click you here is the starter solenoid.
that is where i would start.
you can try tapping on it with a heavy wrench or small hammer while someone is turning the key.

[Christian-]

Originally Posted by Jolly Roger bus 223

the click you here is the starter solenoid.
that is where i would start.
you can try tapping on it with a heavy wrench or small hammer while someone is turning the key.

The solenoid that's connected directly to the starter isn't clicking. I'm not 100% sure where the relay is for the starter, so I can't test that unfortunately.

The click I hear is when the first position on the key is turned. Sometimes there's two or three clicks a second or so apart. It sounds more like some sort of accessory trying to do something.

When we turn the key to actually start it there's no click at all.

[Jolly Roger bus 223]

that sounds like low battery voltage to be honest.
brand new batteries off the shelf are usually not fully charged and a reading of 12.1 or 12.3 is not adequate voltage for starting most diesels.
check your battery wiring and make sure you wired for 24v if you have a 24v system and also look for any other small wires that were attached at the batteries that might have wiggled loose.
your accessory solenoid is probably whats clicking .
if its in and out then it is getting low or bad voltage which could kill your brand batteries as a parasitic draw.

[Christian-]

Originally Posted by Jolly Roger bus 223

that sounds like low battery voltage to be honest.
brand new batteries off the shelf are usually not fully charged and a reading of 12.1 or 12.3 is not adequate voltage for starting most diesels.
check your battery wiring and make sure you wired for 24v if you have a 24v system and also look for any other small wires that were attached at the batteries that might have wiggled loose.
your accessory solenoid is probably whats clicking .
if its in and out then it is getting low or bad voltage which could kill your brand batteries as a parasitic draw.

That was my first thought also, which is why I verified the battery to be known good and had a high amp charger on it when testing and a trickle charge when not.

I've used the multimeter to verify I'm not getting a voltage drop and my connections and cables are good all the way to the starter from the battery.

It definitely seems like something from the ignition switch to the solenoid on the starter itself.

The battery voltage is a solid 12.7v.


There's a whole mess of wiring in the dash and in the side panel and under the hood that isn't entirely clear to me what any of it does. I've read a bit about some of the interlocks and suspect that could be part of the problem also. Could also be the ignition switch. But finding and testing the starter relay or having some wiring diagrams would be a great start.

[Jolly Roger bus 223]

to help us help you we need a little more info?
from what i have read its not your bus.
but we still need you to fill out a profile so everyone here can see year make , model like thomas bluebird international chassis?
all of that makes a difference.
5.9 24v cummins was and is in alot more than than just that bus.
check roof hatches check door latches?
did your friend remove a handi ramp?
**** to check

[Christian-]

Originally Posted by Jolly Roger bus 223

to help us help you we need a little more info?
from what i have read its not your bus.
but we still need you to fill out a profile so everyone here can see year make , model like thomas bluebird international chassis?
all of that makes a difference.
5.9 24v cummins was and is in alot more than than just that bus.
check roof hatches check door latches?
did your friend remove a handi ramp?
**** to check

I'll see if I can fill out my profile later.

As you can see in my first post/subject, the bus is a 2000 and appears to be a Thomas bus built by Freightliner. From photos I've seen online it looks like an FS65 Thomas, for what thatt's worth.

I did check the roof and door latches/hatches, but I'll check them again. A wiring diagram to sort that out would be super helpful.

No ramp removal. Bus has the split/opening door on the passenger side, and two emergency exits. One on the driver's side about halfway down the bus and one in the back.

[Bal00ga]

we have a 24v 5.9 in our 2000 thomas RE and ti wil not start fro the key if any of the Emegency exits are open or the bus thinks its open. I found this out on the maiden voyage home. The drivers side door latch switch was funky and would sometimes not make good contact. You should be able to turn the key to the on position (not try to start) then start it from the engine bay. If that works one of your switches is bad or you have something open.